1. Field of the Invention
The present invention relates to a focal length switching camera in which when a lens unit is not in a normal photographing position at the time of photographing, a user is cautioned or the unit is corrected so as to assume a normal photographing position.
2. Description of the Prior Art
In the past, a lens exchange type camera whose lens can be exchanged with a telephotolens having a long focal length when a remote object is photographed in a large size, has been widely used. However, in this kind of camera, it is cumbersome to carry an in which two kinds of focal lengths may be switched by simple operation has been recently developed.
The two-focus camera of this kind encases therein two optical systems different in focal length from each other and in photographing, either optical system is selected by manual operation. The switching operation of the optical system becomes simpler as compared with prior art camera which involves cumbersome of lens exchange but this exchange requires a certain degree of time and therefore when a moving object is photographed, one might miss a shuttering chance, and it is difficult to switch the focal length while performing framing.
In view of the foregoing, the present inventors have proposed a two-focus camera in which a one optical system is used commonly, and a motor is started by operation of a button to laterally move a main lens unit and move the rear conversion lens into and out of an optical path thereby automatically switching the focal length.
However, in such a camera which automatically switches the focal length, for example, there is a possibility that a power source voltage drops to stop the switching operation during such operation or when the camera is encased into a case, a focal length switching button comes into abutment with a part of the case and as the result the lens-barrel protrudes and remains stopped during the operation.